This is an area that needs work, but basically there's the table of 'edge intensity' that gets multiplied by a constant baseChance variable for every pixel.
baseChance = 8 * samples / (width * height)
samples is the desired number of samples.
Again, this needs work. I'm pretty sure there's a way I can more accurately match the number of output samples to the desired number of samples.
Edit: And no, it can't produce a response if there's no edge (a value of zero). However, there's always some level of noise. This is true of the example you've shown - there's very light noise visible.
baseChance = 8 * samples / (width * height)
samples is the desired number of samples.
Again, this needs work. I'm pretty sure there's a way I can more accurately match the number of output samples to the desired number of samples.
Edit: And no, it can't produce a response if there's no edge (a value of zero). However, there's always some level of noise. This is true of the example you've shown - there's very light noise visible.